1. Field of the Invention
The invention pertains to a portable envelope feeder used with an offset printing press. More specifically, this invention pertains to a simple feeder that can be used with a multiple of offset printers.
2. Description of the Prior Art
The offset printer is an inexpensive and desirable way to print a substantial number of items such as sheet stock and envelopes. However, most offset printers are designed for sheet stock with an inefficient and slow method of printing envelopes. Usually it resorts to being a hand fed operation. There are, however, offset printers that are solely dedicated to printing envelopes that contain automatic and complicated envelope feeding mechanisms permanently attached to the printer. For the small printing shop the cost of having an offset printer sitting idle most of the time and used only to print envelops cannot be tolerated. In order to prevent either a slow hand fed operation or a dedicated printer for solely envelopes, the present invention provides a simple portable envelope feeder that can be set up in a matter of minutes and feed a stack of envelopes to the offset printer as quickly as sheet stock can be fed. The feeder can hold an entire box (500 envelops) or any portion thereof and provide an efficient and reliable feeder for envelopes of a plurality of standard sizes. It is also estimated that the present envelope feeder can be used on 12 different offset printers presently in use.
There are a number of envelope feeders in use today but most have the drawback of being dedicated to a specific offset printer. There is, however, an envelope feeder that is designed to feed multiple stacks into an offset printer. This feeder is described in U.S. Pat. No. 4,625,641 to Jagosy et al. The structure is considerably different from the present invention, however, as only one stack at a time is fed by the present invention into the offset printer. The mechanism in Jagosy et al that is used to change to a different size envelope is also completely different from the one described in the present invention. While it appears that the feeding system described by Jagosy et al will fit on some type of offset printers of which he designates at 10, he is completely silent on what type or model of printer that can utilize his feeding mechanism.
Another apparatus for feeding envelopes is described in U.S. Pat. No. 2,130,101 by Ritzerfeld. This device does not use any suction device as in the present invention but uses a flat tang like plate to pull the envelops of the bottom of the stack.
Still another envelope feeder apparatus is U.S. Pat. No. 4,431,323 to Kulow. This invention relates to a system for serially feeding envelops to a printing machine such as a typewriter which is unlike the feeder of the present invention.
What is needed is an inexpensive, simple portable feeder that can be adjusted to fit a substantial number of offset printing presses in addition to accepting a plurality of envelope sizes. In this manner a small printing shop can have one offset printer that can normally print flat stock and in minutes convert the same offset printer to a high speed envelope printer.